The present invention relates to a remote interactive system including a host system with an instructor console for use by an instructor and at least one remote system intended to be located geographically remote from the host system. A communication system between the host system and a base unit at the remote system communicates an audio-video signal from the instructor to the remote site and an audio signal from the base unit to the host system thereby allowing interactive interaction between an instructor and one or more users, or respondents, at the remote site.
In such a remote interactive system, it is common to use a phone line to provide the audio link from the remote site to the host system. This typically requires an audio bridge to handle incoming calls from the remote sites. The audio bridge is typically a complicated computer-based system which is capable of handling many incoming calls. The audio bridge answers each incoming call and notifies the instructor at the instructor console of the call. Typically, a human will talk with the person placing the call in order to attempt to verify the authenticity thereby removing harassing calls from being placed to the instructor. Such system has many drawbacks. It is expensive and complicated and requires human intervention in order to attempt to eliminate calls originating from outside of the multiple-site interactive response system. This is not always possible if the caller is clever enough to convince the human intervenor that he/she is present at one of the sites. Therefore, the known audio bridge is unsatisfactory.
Another difficulty with multiple-site interactive response systems is in regulating the audio level of incoming calls to the host system. It is well known that the quality of phone line connection varies greatly from call-to-call. Therefore, if multiple sites are placing calls to the instructor console, the audio quality will typically be different for each site. Prior systems have attempted to overcome such variation in line quality by providing automatic gain control on the line. Such prior art automatic gain control works off the audio signal, namely the speaker""s voice signal. The problem is that when the speaker pauses, the absence of a signal causes the automatic gain control to increase the gain. When the speaker then begins to speak, the automatic gain control reduces the gain in response to the voice signal. This results in a xe2x80x9cpumpingxe2x80x9d of the gain which tends to amplify background noises and results in an overall unsatisfactory voice quality.
Remote site interactive systems usually include an instructor studio having an audio-video capture device, such as a video camera, and a communication channel to transmit the audio-video signal to the remote site or sites. The audio-video signal may be transmitted by any one of a number of means, such as a physical cable, a satellite link, or the like. Various transmission systems introduce delay into the signal which, typically, varies from system-to-system. Furthermore, even within a particular type of system, such as satellite transmission, various delays can be introduced by the transmission path. For example, if the transmission path is up to the satellite and down to the site, one delay will be encountered. If, instead, the signal is handed off from the first satellite to one or more secondary satellites and then to the site, a second, different, delay will be encountered. Other anomalies result in signal delay. For example, it is common to utilize signal compression and decompression in order to minimize transmission bandwidth. The compression and decompression process adds further delay to the signal. As a result, it is not uncommon to have as much as several seconds in delay between the signal origination at the instructor""s studio and the image display at the remote site. Furthermore, the delay may be different from site-to-site. One site may utilize a satellite system and another site may utilize a cable system. In order to compensate for the delay, it is known to provide a muting function at the site. The muting function is built in to the system which xe2x80x9chands offxe2x80x9d the two-way communication between the remote site and the instructor host site. Thus, as long as an instructor is talking, the microphone at the remote site is xe2x80x9cdeadxe2x80x9d so that the person at the remote site cannot speak to the instructor. When the instructor pauses, the microphone at the remote site becomes xe2x80x9clivexe2x80x9d and the person at the remote site can speak. Because of the delay between the audio-video signal of the instructor and its receipt at the remote site, it is necessary to delay activation of the instructor""s signal for a period of time at that remote site after the person at the remote site is finished talking in order to avoid coupling a portion of the person at that remote site""s speech through the instructor consoles out to that remote site. It is desirable that the length of such muting is made equal to the delay in transmission from the instructor""s console to the particular remote site. In the past, this has been accomplished by positioning a skilled technician at each remote site prior to its use. The technician manually sets the muting length by talking into the respondent""s microphone and waiting for the signal to arrive back at that remote site through the host system. Such manual setting technique is undesirable because it requires a skilled technician to be located at each site, at least during its initial setup, and the manual adjustment of the muting which is a subjective procedure. If the muting is set too long, then there is an unnecessary delay in the communication between the instructor and each of the remote sites and a portion of the instructor""s audio may be lost. If the muting is set too short, then a portion of the person at the particular remote site is captured at the instructor""s console and forwarded to that remote site.
In multiple-site interactive response systems, it is known to provide response units to each of a plurality of users at a particular remote with a microphone built into each response unit. When a respondent wishes to address the instructor, the respondent signals by activating a xe2x80x9ctalk requestxe2x80x9d button which is communicated to the instructor""s console. If the instructor selects that respondent, the system opens an audio signal from the microphone in the corresponding response unit to the instructor""s console typically over a phone line. If the user places the response system far away from the user""s mouth, such as on a desk surface in front of the user, the gain of the system must be set high enough to receive the voice of the user at a significant distance. If there is noise in the room, such as laughter, then the gain necessary to receive the speaker""s voice at such distance will cause background noise to be picked up by the microphone. The background noise level can be great enough, especially in the case of laughter, that the system may not be able to xe2x80x9chand offxe2x80x9d the user to the instructor. If the situation is remedied by decreasing the gain, then the only way the student can use the response unit is to hold the microphone close to the mouth of the user. However, by lowering the gain, the system will not adequately receive the user""s voice if the response unit is placed far away from the user, such as on a desk. While it is known to provide audio compression in order to attempt to solve this problem, audio compression alone is inadequate to completely solve the problem.
The present invention provides a multiple-site interactive response system which overcomes the difficulties in the prior art in a manner which is effective and cost efficient.
According to an aspect of the invention, a remote interactive system includes a host system having an instructor console and at least one remote system having a base unit. A communication system is provided between the host system and the base unit which is adapted to communicate an instructor audio signal from the host system to the base unit and a responding audio signal from the base unit to the host system. According to this aspect of the invention, the communication system includes an audio enhancer which enhances one or more of the signal level, signal muting, and signal source authenticity between the instructor and the base unit.
According to another somewhat more detailed aspect of the invention, an interactive system for providing interaction between an instructor at an instructor location and a plurality of respondents located at at least one geographically separated site is provided wherein the interactive system is useful with an audio-video transmission system including a studio at the instructor location having audio-video equipment which supplies audio-video information and a communication system which downloads audio-video information from the audio-video equipment to an audio-video monitor at the geographically separated site. The interactive system includes a host system having an instructor console and an instructor microphone adapted to be used in a studio. The host system further includes a phone line manager adapted to be connected with at least one phone line. At least one remote system has a base unit and at least one respondent microphone wherein the base unit is adapted to be connected to at least one phone line. According to this aspect of the invention, the host system coordinates with the base unit to level the output of a phone line transmission from the base unit to the phone line manager. This may be carried out, according to the preferred embodiment, by the host system instructing the base unit to send a reference tone which is received by the phone line manager. The phone line manager, under command of the host computer, adjusts its gain in response to the level of the signal received. In this manner, the line is normalized without the use of the speaker""s voice. This avoids the xe2x80x9cpumpingxe2x80x9d action in the prior art. This allows multiple lines from multiple sites to be equalized notwithstanding substantial variation in line quality from each of the sites.
According to another aspect of the invention, in such interactive system, the host system coordinates with the base unit to validate phone calls received by the phone line manager. In a preferred embodiment, this is accomplished by the host system instructing the base unit to send a coded signal. The phone line manager then responds only if such coded signal is received from the base unit. If a phone call is placed to the phone line manager, which does not include such coded signal, the phone line is disconnected. This provides exceptional integrity to the system because it ensures that only phone calls can be placed from remote sites and anyone attempting to dial into the system from elsewhere, except from a particular remote site, will be ignored.
According to another aspect of the invention, in such an interactive system, the host system coordinates with the base unit to measure communication system delay between audio-video equipment in an instructor""s studio and an audio-video monitor at the geographically separated site. In a preferred embodiment, this is accomplished by the host system sending a test signal over the communication system which the base unit receives. The host system is informed when the test signal is received which thereby determines the amount of delay. This delay is used to establish muting of the audio-video system.
According to yet another aspect of the invention, in such an interactive system, the host system has control over the sensitivity of the respondent microphone at the base unit. In a preferred embodiment, the host system is capable of switching the respondent microphone between a xe2x80x9cClose Talkxe2x80x9d and xe2x80x9cFar Talkxe2x80x9d state. In the xe2x80x9cClose Talkxe2x80x9d state, the respondent microphone has a lower gain. In the xe2x80x9cFar Talkxe2x80x9d state, the respondent microphone has a higher gain. This allows the host system to have control over the particular arrangement of the host site. This is especially desirable when the respondent microphone is located in each of a plurality of response units which are provided to users such that the user talks directly into a microphone in that user""s response unit.
A method of enhancing audio signal transmission from either the host system or the base unit to the other of the host system or the base unit in such interactive system, according to an aspect of the invention, includes sending a test signal from either the host system or the base unit and analyzing the test signal received at the other of the host system or the base unit. This provides the unique ability to enhance the audio signal transmission by facilitating automatic enhancement of signal level, signal muting, and signal source authenticity.